Eurocode 1: Actions on structures – Part 1–2: General actions – Actions on structures exposed to fire Part of the One Stop Shop program Annex B (informative) → Thermal actions for external members – Simplified calculation method

Introduction This method allows –Determination of maximum compartment temperatures –Determination of size and temperatures of flame from openings –Determination of radiation and convection parameters This method is only valid for fire loads higher than 200 MJ/m 2

Ventilation mode Forced draught conditions –If there are windows on opposite sides of the compartment (or air is being fed from another source) No forced draught conditions –If the windows in one side of the compartment are the only source of fresh air

No forced draught The heat release rate is given by The temperature of the compartment is given by The flame height is given by No forced draught

D / W ratio When there are windows only in Wall 1 When there are windows only in more than one wall When there is a core in the fire compartment Sum of window widths Width of wall perpendicular to Wall 1 Width of Wall 1 (assumed to have greatest window area) Sum of window areas on Wall 1 Total area of vertical openings Length and width of the core Length and width of the compartment

Flame width Horizontal cross-section of opening The flame width is taken as equal to the width of the opening from which it is projected No forced draught

Flame depth Vertical cross-section of opening The flame depth is 2/3 of the window height No forced draught

Horizontal flame projection - Wall above window Vertical cross-section of opening In the case of a wall existing above the window For And the distance to another window In all other cases No forced draught

Axial Flame Length - Wall above window Vertical cross-section of opening In the case of a wall existing above the window or if as No forced draught

Flame projection and length - NO Wall above window Vertical cross-section of opening In the case of a wall not existing above the window, the horizontal projection of the flame is given by The flame length along the axis can be given as No forced draught

Flame temperature The flame temperature at the window is given by with The flame temperature along the axis is given by with The emissivity of flames may be taken as The convective heat transfer coefficient is given by Flame thickness No forced draught

Forced draught The heat release rate is given by The temperature of the compartment is given by The flame height is given by Forced draught

Flame dimensions Forced draught Horizontal cross-section Vertical cross-section Horizontal projection of flame is given by Flame width Flame length along axis

Flame temperature The flame temperature at the window is given by with The flame temperature along the axis is given by The emissivity of flames may be taken as The convective heat transfer coefficient is given by Flame thickness Forced draught The emissivity of flames at the window may be taken as

Awnings and Balconies If located at the top of the window (across whole width with wall above window) and the following adjustments should be made –Flame height should be decreased by –Horizontal projection should be increased by For NO wall above, or –Flame height should be decreased by –Horizontal projection should be increased by No forced draught

Configuration factors The overall configuration factor of a member for radiative heat transfer from an opening should be determined from is the configuration factor of member face i for that opening is the cross-sectional dimension of member face i is the protection coefficient of member face i: protected unprotected